Tubulous support wall



June 1967 J. 5. GCDLDSACK 3,

TUBULOUS S UPPORT WALL Filed Feb. 15, 1966 5 Sheets-Sheet l I4 52 INVENTOH JOHNS. GOLDSACK 5 Sheets-Sheet Filed Feb. 15, 1966 June 6, 1967 J. 5. GOLDSACK TUBULOUS SUPPORT WAL Filed Feb. 15, 1966 3 Sheets-Sheet 5 United States Patent 3,323,496 TUBULOUS SUPPORT WALL John S. Goldsack, London, England, assignor to Babcoclr E: Wilcox, Limited, London, England, a corporation of Great Britain Filed Feb. 15, 1966, Ser. No. 527,553 Claims priority, application Great Britain, Feb. 17, 1965, 6,826/ 65 10 Claims. (Cl. 122-510) This invention relates to tubulous support walls and, more particularly, to tubulous support walls provided in vapor generating and vapor superheating units. Such walls, or arrays, may form division or boundary walls, which may be pervious, in a convection heat exchange pass leading from a furnace chamber of the unit, which may operate with either natural or forced circulation of the working medium, and include upright tubes which are provided with support means arranged to support tubes extending horizontally across the pass.

A tubulous support wall, or array, of upright tubes provided with support means arranged to support horizontally extending tube banks according to the present invention includes a first row of tubes extending downwardly from a header intermediate the height of the wall to a lower header, a second row of tubes extending upwardly in groups from the lower header to tube junctions at a level intermediate the height of the wall and a thirdrow of tubes composed of tubes extending upwardly, one from each tube junction, connecting into an upper header.

Such a support wall may be used in supporting one or more tube banks in for example a downfiow gas pass independently of the support of bounding walls of the pass. Moreover, it allows being cooled by fluid, for example, economizer water, from the tube bank. Moreover, it is more particularly suitable for supporting in a downfiow gas pass a vapor reheater of relatively large tube pitching above an economizer tube bank of relatively small tube pitching and so that all support tubes take part of the load and while properly spacing the tubes in the banks. These and other advantages will be further mentioned in the subsequent descriptions herein.

The invention will now be described by way of exampie with reference to the accompanying drawings, in which:

FIGURE 1 is a diagrammatic sectional elevation of a downfiow gas pass of a steam boiler, said pass containing reheater and economizer tube banks and support walls therefor;

FIGURE 2 schematically indicates the relations between certain tube rows;

FIGURE 3 is an elevation showing parts of one of the support walls; and

FIGURE 4 illustrates a modification applicable to the constructions of the support walls.

Referring to FIGURES 1 to 3 of the drawings, a convection heat exchange pass 1 of a steam boiler is arranged for the downward flow of gases therein in series over a horizontally extending reheater tube bank 2, an upper horizontally extending economizer tube bank 3 arranged below the reheater tube bank 2 and a lower horizontally extending tube bank 4 arranged below the upper economizer tube bank 3. The gases are the combustion gases of the boiler furnace chamber (not shown) of which they leave the upper part to flow rearwardly through a gas pasage 5 leading to the upper end of the downfiow gas pass 1, which provides a space 6 above the uppermost horizontal tube bank wherein gases may turn for downward flow over the tube banks 2, 3 and 4. The pass 1 also contains a vertically extending reheater tube bank 7 in the path of gases flowing from the gas passage 5 to the gas turning space 6.

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The front wall 8 of the gas pass 1 is fluid-cooled by a row of vertical tubes 9 extending between a lower header or headers 10 and an upper header or headers 11, the rear wall 12 thereof is cooled by a row of vertical tubes 13 extending between a lower header or headers 14 and an upper header or headers 15, and the side walls 21 thereof are cooled by rows of vertical tubes 22 extending between lower headers 23 and upper headers 24. The upper headers 11, 15 and 24 are supported from structural members 25 by suspension means 26 which, in the construction indicated, include springs 27. The roof 28 of the gas pass 1 is fluid-cooled by a row of tubes 29.

The economizer tube banks 3 and 4- consist of horizontal rows one above the other of tubes 30, each of which is connected for flow from one or other of two economizer inlet headers 31 and 32 extending transversely across the gas pass below the bank 4, extends in sinuous fashion backwards and forwards in the bank 4, extends vertically in a space 33 between the banks 3 and 4, extends in sinuous fashion backwards and forwards in the bank 3 and connects into one or other of two economizer outlet headers or collectors 34 annd 35 extending transversely across the gas pass above the bank 3.

The reheater tube bank 2 consists of horizontal rows one above the other of tubes 39, each of which is connected for flow from one or other of two reheater inlet headers 40 and 41 extending transversely across the gas pass 1 below the bank 2 and extends in sinuous fashion backwards and forwards in the bank 2. Each of the tubes 41 then extends upwards and downwards in sinuous fashion in the vertically extending reheater tube bank 7, after which it extends forwardly to a further reheater tube bank (not shown) positioned in the gas passage 5.

The horizontally extending tube banks 12, 3 and 4 are supported by two support walls 42 and 43 each of which extends in a vertical plane from top to bottom of the gas pass 1 and from side to side thereof. Each support wall comprises upright tubes which, in a manner to be described, are cooled by water that has traversed the econ omizer tube banks 4 and 3.. The upright tubes of the support wall act as spacers between adjacent tubes in the horizontal rows of the said banks and are provided with suitable support means for tubes of the said banks.

The front support wall 42 includes a first row of tubes 44 which extend forwardly from the front economizer outlet header 34 and then downwardly in the plane of the wall to connect into a horizontal lower header 45 at the bottom of the wall. The said wall includes a second row of tubes 44 which spring from the lower header 45 and, in pairs alternating with the first row tubes 44 extend upwardly in the plane of the wall to a level above the upper economizer tube bank 3, where the tubes of the pairs of second row tubes 44 connect into respective tube junctions or bifurcations 46. The wall includes a third row of tubes 44 composed of tubes extending upwardly in the plane of the wall, one from each tube junction 46 and connecting into a horizontal upper header 47. The wall also includes a fourth row of tubes 44 which extends forwardly from the front economizer outlet header 34 and then upwardly in the plane of the wall to connect into the upper header 47. The third and fourth row tubes 44 and 44 alternate across the support wall.

The first and second row tubes 44 and 44 are spaced with uniform pitch across the wall and act as spacers between adjacent tubes in the horizontal tube rows of the economizer tube banks 3 and 4. The third and fourth row tubes 44 and 44 are spaced with uniform pitch across the wall and act as spacers between adjacent tubes in the horizontal tube rows of the reheater tube bank 2.

FIGURE 2 shows schematically without regard to scale the dispositions of the tube rows 44 44 44 and 44 in relation to one another and to the tubes and 39 of the tube banks.

For the support of the economizer, tube bank lugs are provided on the second row tubes 44 Referring to FIG- URE 3, of the lowermost horizontal row of the upper economizer tube bank 2 each economizer tube which extends between a first row tube 44 and a second row tube 44 is supported by a lug 48 welded to the second row tube and projecting into the space between the first row tube and the second row tube and each economizer tube which extends between two second row tubes 44 is supported through a saddle 49 by two co-operating lugs '50, one welded to each of the two second row tubes, which project into the space between the two second row tubes. Each of the other horizontal tube rows of the upper economizer tube bank is supported on and spaced from the horizontal tube row therebeneath by suitable chairs or spacer blocks 51, on which the tubes of the upper row respectively rest and which are welded to the respective tubes of the adjacent lower row. An entirely similar arrangement of lugs on the second row tubes 44 is provided for the support of the lower economizer tube bank 4, the horizontal tube rows of which are spaced apart from one another by suitable chairs or spacer blocks. The first row tubes 44 do not carry any of the weight of the economizer banks and in a modification are not in the vertical plane of the remaining tube lengths in the wall.

For the support of the horizontally extending reheater tube bank 2 lugs are provided on the fourth row tubes 44*. Referring to FIGURE 3, each tube 39 of the lowermost horizontal tube row of the reheater bank 2 is supported by a lug 52 welded to the adjacent fourth row tube 44 The tubes of each of the other horizontal tube rows of the bank 2 rest on suitable chairs or spacer blocks 53 welded to the respective tubes of the horizontal tube row therebeneath.

The support wall upper header 47 is positioned above the roof 28 of the gas pass 1 and is supported from the structural members 25 by suitable suspension means 55 which, as shown, include springs 56.

The rear support wall 43 is entirely similar in its formation and in its function to the front support wall, the only difference being that it receives its cooling water from the rear economizer outlet header which is in front of the rear support wall. Thus the rear support wall 43 comprises a first row of tubes 61 extending rearwardly from the rear economizer outlet header 35 to the wall and then downwardly in the wall to a lower header 62, a second row of tubes 61 extending upwardly in the wall in pairs from the lower header 62 to tube junctions or bifurcations (not shown) at a level above the upper economizer bank 3, a third row of tubes 61 extending in the wall upwardly from the tube junctions to an upper header 63 and a fourth row of tubes 61 extending rearwardly from the rear economizer outlet header 35 to the wall and then upwardly in the wall to the upper header 63. Lugs (not shown) are provided on the second row tubes 61 for economizer bank support and on the fourth row tubes 61 for reheater bank support.

The economizer headers 31, 32, 34 and 35 are so associated with the economizer banks 3 and 4 through the numerous economizer tubes and by additional ties to the economizer banks as may be necessary as to be supported by said tube banks; similarly the reheater headers and 41 are supported by the reheater tube bank 2.

In the operation of the boiler, the water flows generally upwardly in the economizer tube banks 3 and 4, as is usually desirable in steam boiler economizers. Although the economizer outlet headers 34 and 35 are above the economizer banks 3 and 4, the arrangement provide-s for the cooling of the support walls 42 and 43 extending throughout the height of the gas pass I by water from the economizer, whereby the expansions of the support walls are limited. The reheater bank 2 and the economizer banks 3 and 4 are supported without the necessity for supporting beams extending across the gas pass from one gas pass wall to the other, the use of which leads to thermal expansion and other difiiculties. The banks 2, 3 and 4 are supported independently of the gas pass walls 8, 12 and 21, which may therefore be cooled by working fluid of the boiler such as saturated water or by steam as may be convenient, capable of causing thermal expansions in the gas pass walls ditferent from those that take place in the support walls.

No rows of support wall tubes need be made strong enough to take the weights of all the horizontally extending tube banks 2, 3 and 4 since the weight of the tube bank 2 is taken by rows of support wall tubes different from the rows of support wall tubes which take the weights of the tube banks 3 and 4.

The support wall constructions allow the reheater tubes, spaced by the third and fourth rows of the support wall tubes and supported by the fourth rows thereof, to be of larger diameters than the economizer tubes and to be arranged with a greater pitch in the horizontal tube rows thereof than the economizer tubes. It will be understood that economizer tubes in a boiler will generally require to be of smaller diameter and more closely spaced across the gas flow than steam heating tubes in a hotter region of the gas path.

It will be understood that it may be desirable to ensure before starting up the boiler that all the economizer tubes and all the support wall tubes are filled with water throughout to which end the wall upper headers 47 and 63 are provided with respective vent connections (not shown). The wall lower headers 45 and 62 are provided with respective drain connections (not shown).

In the boiler envisaged the support walls 42 and 43 are cooled by only part of the water from the economizer tube banks, the remainder of the water being taken from the economizer outlet headers 34 and 35 through connectors (not shown) leading to further heating surfaces of the boiler.

Means may be provided for locating the upper ends of the lengths in the support wall 42 of the first row of support wall tubes 44 in relation to respective lower ends of the lengths in the wall of the fourth row of support wall tubes 44*. Such means may be adapted to enable the first row tubes to carry some of the weight of the economizer tube banks, the load on the first row tubes being transferred to the fourth row tubes. In the example of such expedient illustrated in FIGURE 4, the length in the plane of the support wall 42 of each of the first row tubes 44 and the length co-axial therewith in the plane of the wall of the corresponding fourth row tubes 44 are provided by a single tube 144 having a diaphragm 145 therein which separates the downfiow water'space in the tube lengths 44 in the wall from the upfiow water space in the tube length 44 in the wall. The tube lengths 44 in the wall, that is to say the lower lengths'of the tubes 144, may be provided with lugs whereby to receive the weight of one of the economizer tube banks, if thereby the thirdand fourth row tubes 44 and 44 may be more equally loaded. It will be understood that a similar arrangementmay. be used in the rear support wall 43.

I claim:

1. In a vapor generator, boundary walls defining an upright heating gas pass, a bank of transversely extending fluid heating tubes disposed within said gas pass, tubulous wall means within said gas pass arranged for the support of said bank of tubes independent of said boundary wall, a cooling fluid inlet header disposed within saidgas pass intermediate the height of said wall means, a first collection header connected with the lower end of said wall means, a second collection header disposed above and connected with the upper end of said wall means, means for passing cooling fluid directly from said inlet header downwardly through said wall means to said lower collection header, means for passing cooling fluid from said inlet header upwardly through said wall means to said upper collection header, and means connecting said wall means to said bank of tubes for the support thereof.

2. The invention according to claim 1 wherein said lower collection header is a transfer header, said upper collection header is a cooling fluid outlet header, and said wall means includes a first row of tubes connected with and extending downwardly from said inlet header to said transfer header, a second row of tubes connected with and extending upwardly from said transfer header, tube junction means at a level intermediate the height of said wall means, said second row of tubes being con nected with said tube junction means, and a third row of tubes connected with said tube junction means and extending upwardly therefrom to connect with the cooling fluid outlet header.

3. The invention according to claim 2 wherein there are provided support lugs attached only to said second row of tubes for the support of said bank of tubes.

4. The invention according to claim 3 wherein a group of tubes of said second row is connected for flow of cooling fluid through said tube junction means to a smaller number of tubes of said third row.

5. The invention according to claim 3 wherein the first mentioned bank of tubes is economizer heating surface arranged to discharge preheater feedwater into said cooling fluid inlet header.

6. The invention according to claim 5 further including an additionalbank of transversely extending fluid heating tubes disposed within said gas pass, means for passing superheated vapor through the tubes of said additional bank of tubes, a fourth row of tubes connected directly with and extending upwardly from said cooling fluid inlet header to said cooling fluid outlet header, and support lugs attached only to said fourth row of tubes for the support of said additional bank of tubes.

7. The invention according to claim 6 wherein the tubes of said third and fourth rows are alternatively disposed between adjacent tubes of said additional tube bank to thereby serve as spacers, and wherein the tubes of said first and second rows are disposed between adjacent tubes of the first mentioned tube bank to thereby serve as spacers.

8. The invention according to claim 6 wherein the tubes of said first row are in longitudinal alignment and rigidly connected with the tubes of said fourth row, whereby loading on the first row of tubes is picked up by said fourth row of tubes.

9. The invention according to claim 8 further including an intermediate bank of transversely extending fluid heating tubes disposed within said gas pass between the first mentioned tube bank and said additional tube bank, and support lugs attached only to said first row of tubes for the support of said intermediate tube bank.

10. The invention according to claim 9 wherein the intermediate tube bank is connected for flow of feedwater from the first mentioned tube b ank and to said cooling fluid inlet header.

References Cited UNITED STATES PATENTS 1,932,918 10/1933 Abendroth 122-235 3,081,748 3/1963 Koch 122406 3,102,514 9/1963 Armacost 122-480 KENNETH W. SPRAGUE, Primary Examiner. 

1. IN A VAPOR GENERATOR, BOUNDARY WALLS DEFINING AN UPRIGHT HEATING GAS PASS, A BANK OF TRANSVERSELY EXTENDING FLUID HEATING TUBES DISPOSED WITHIN SAID GAS PASS, TUBULOUS WALL MEANS WITHIN SAID GAS PASS ARRANGED FOR THE SUPPORT OF SAID BANK OF TUBES INDEPENDENT OF SAID BOUNDARY WALL, A COOLING FLUID INLET HEADER DISPOSED WITHIN SAID GAS PASS INTERMEDIATE THE HEIGHT OF SAID WALL MEANS, A FIRST COLLECTION HEADER CONNECTED WITH THE LOWER END OF SAID WALL MEANS, A SECOND COLLECTION HEADER DISPOSED ABOVE AND CONNECTED WITH THE UPPER END OF SAID 